This invention relates to a separator for separating solid particles from a gas stream in which the particles are entrained. The separator comprises a rotatable member on which the entrained particles impinge during operation and the axis of rotation of the member being non-vertical. The rotatable member may be an impeller which impels the gas stream through the separator. Additionally or alternatively, the rotatable member may be arranged for separating the particles by causing impaction of the particles on the rotatable member.
Particularly in a case where the rotatable member itself separates the particles from the gas stream by impaction of the particles on the rotatable member, but also in other cases where the rotatable member is contacted by the gas stream carrying particles, the separated matter can accumulate on the rotatable member. If such accumulation is not distributed symmetrically around the axis of rotation and longitudinally of the axis, then the accumulation will result in the presence of an out-of-balance mass on the rotatable member. The presence of such an out-of-balance mass tends to cause the member to vibrate as it is rotated and such vibration causes excessive wear and excessive emission of noise. Accordingly, when solid matter accumulates on the rotatable member of apparatus of the kind specified, it is necessary either to clean the member or to replace it.